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Full text of "The Morphology And Evolution Of The Apes And Man"

THE ORDER PRIMATES
support; it may also act as an equipoise when the animal is performing its characteristic froglike leaps. It also acts as an equipoise in the Old World ifangabeys (Cercocebus), which are active jumpers; and it is an important prehensile organ in the New World Monkeys. The tail is a mere rudiment in the Baboons, and it is absent in the Anthropoid Apes and Man. In the Apes and Man ,the muscles of the tail have been transformed into the muscles of the pelvic floor, which plays an important part in supporting the abdominal viscera in the erect or semi-erect position.
The eyes are large in the Lemurs, Tarsiits and Gibbons, but, as will be shown later, there are profound differences between the ocular apparatus in the Gibbons and that in the Lemurs and Tarsius. Large eyes are associated with nocturnal habits, and there appears to be an inverse ratio between the dimensions of the eyes and the size and bulk of the animal. Thus the eyes are small in the Chimpanzee and large in the Gibbons.
All Primates except Man and the Orang have a triangular process beneath the tongue for the openings of the ducts of the submaxillary glands; and some have an additional body, or sublingua, which is best marked in the Lemurs. The stomach is simple in all except the Langurs and Guerezas, and the entire large intestine has a well-marked mesentery in all Primates below the Anthropoid Apes; in the latter long stretches of the colon are bound down to the posterior abdominal wall, an arrangement which is associated with the erect or semi-erect attitude.
The testes descend into a scrotum, and the penis has